Hydraulic steering device



2 SHEETS-SHEET 1 Filed July 31, 1947 INVENTOR JHCOBUS NOORDEMBN PIETER JAM o1.

ATTORNEYS Oct. 23, 1951 P. J. NOORDEMAN HYDRAULIC STEERING DEVICE 2 SHEETS-SHEET 2 Filed July 31, 1947 Fig.2

g Q FA L n 7 //////V/////////////%////// Fig.3

ATTORNEYS Patented Oct. 23, 1951 OFFICE HYDRAULIC STEERING DEVICE Pieter Jacobus Noordeman, Rotterdam, Netherlands Application July 31, 1947, Serial No. 765,060 In the Netherlands June 21, 1946 Section 1, Public Law 690, August 8, 1948 Patent expires June 21, 1966 10 Claims.

The invention relates to a hydraulic steering gear, in which the hydraulic pressure spaces working in opposition are interconnected by a passage provided with a partitioning member which tends to yield in the case of an excessive pressure difference between the hydraulic pressure spaces as may, for instance be the result of an accidental deflection of the rudder, e. g. when the waves wash more or less violently against the rudder. In devices of this type as heretofore known, the said partitioning member includes a safety valve, which opens when the excessive pressure difference has attained a given level and causes hydraulic fluid to overflow between the hydraulic pressure spaces working in opposition. The said excessive pressure difference occurs when the rudder is struck by heavy seas. In that case it is forcibly wrenched out of its position. The safety valve is intended to prevent inadmissibly high pressures in. the system, which might cause damage.

These known devices have, however, the following drawbacks. In the first place, any increase in pressure owing to more or less heavy seas striking the rudder is sudden. The hydraulic systems completely filled with incompressible fluid do not allow of the least yield of the rudder, at least not until the seas are so heavy that the said sudden hydraulic pressure difference causes a risk of damaging the mechanism (cracking), and only thereupon the safety valve starts working and then has to clear a proper passage, while in any case the overflow still has to begin. Then the system may already have cracked. Thus the safety valve works too late and too slowly.

The second drawback consists in that in the case of a sudden pressure difference caused by the wash striking against the rudder, as a result of which the bypass pressure is reached, the fluid bypass does make the deviation or yield of the rudder possible, but, since at the very moment at which the bypassing starts the pump is at once automatically adjusted against the said high pressure, the pump also immediately counteracts the deviation, i. e., the yield in the system is entirely or partially obviated. The rudder is, therefore, in the desired position, immovable in the first case and resistant to deviation in the second case, so that in heavy seas the construction is continuously exposed to alternating violent tensions.

A third drawback is the stiifness of the posi- 7 tion of the rudder. The latter is not put into motion until the critical hydraulic pressure difference is reached. For the rest the rudder is 2 immovable, but this implies an excessive resistance to sailing speed exerted by the rudder when it is not in the central position. In fact. when the rudder has been put beyond the central position it produces a certain resistance to the sailing speed of the ship corresponding to the desired rudder eflect. If then the rudder is struck by the waves, it will suddenly produce a much greater rudder effect than is necessary, which does not affect the position of the ship owing to its short duration, but which does become perceptible in its efiect on the speed resistance of the ship. From the point of view of rudder effect there would be no objection to an elastic deflection of the rudder due the flow of the waves, and from the point of view of speed resistance it would even be highly desirable and in the long run would no doubt result in increased average speed during a longer period.

In this connection it may be observed that in the case of many non-hydraulic steering gears the rudder may deflect elastically indeed (for example owing to elasticity of the tiller-ropes), and that this is considered favourable.

The invention meets the above drawbacks and renders the improvement referred to. To this end, according to the invention the above mentioned partitioning member between the hydraulic pressure spaces, which deflects at the pressure difference, owing to more or less heavy wash of the waves against the rudder, has been designed as a yieldable, movable wall, the deflection taking place against spring tension. When the rudder is struck by the waves, it may deflect slightly, but it is returned by the spring tension only.

In the drawing an embodiment of the invention is illustrated diagrammatically.

Fig. 1 is a general plan;

Fig. 2 is a section through a detail taken on the line IIII in Fig. 1;

Fig. 3 is a section taken on the line III-III in Fig. 1.

The hydraulic system consists of the hydraulic cylinders I, 2, 3 and I, of which the former two and the latter two work in opposition. In the cylinders 2 and l, which have been illustrated partly in section, the ram plungers 5 and 6 are to be seen. Corresponding ram plungers are to be found in the cylinders I and 3. The rods connecting the plungers are arranged in pairs and coupled rotatably with the ends of a cross-head I, mounted on the rudder shaft 8 of the rudder 9.

The cylinders l and 4 and the cylinders 2 and 3 respectively are connected by the conduits l0 and H. The pump is designated by It and the 3 engine driving it by I5. The pump is preferably a Hele-Shaw pump, the direction of flow of which can be completely reversed, while the output may be continuously varied between zero and two maximums (i. e. one maximum in either direction). From the pump I4 a conduit I2 passes to the cylinder I and a conduit I3 to the cylinder 2. The controlling device of the pump I4 i actu ted b the rod I8, which is connected S a y lofluid to be bypassed. With a slight difference one end of the lever I6, the other end 39 of which is engaged by the actuating rod I'I.

When the actuating rod I1 is moved, the said controlling device is operated, as a result of which pressure fluid either enters the cylinders I and 4 via the conduits I2 and I or enters the cylinders 2 and 3 via the conduits I3 and II. In the former case the plungers are driven out of the cylinders I and 4, so that the rudder shaft 8 will be rotated in anti-clockwise direction from the position indicated in Fig. 1. The fluid consequently expelled from the cylinders 3 and 2 returns to the pump I4 through the conduits II and I3. When the controlling device of the pump I4 is moved in the reverse direction and the conduit I3 acts as pressure line, the rudder shaft will turn in clockwise direction. In this case the conduit I2 acts as return line.

There are thus two separate fluid systems, formed by the cylinders I and 4 on the one hand and the cylinders 2 and 3 on the other hand. They are interconnected by a cylindrical tubing I9, in which a piston 20 can move. This piston is mounted on a piston rod 2I, which extends in both directions and leaves the fluid system by means of stufling boxes. On this piston rod 2I, on either side of the piston 20, spring systems have been mounted in the following manner:

The piston rod 2| bears two shoulders or abut ments 22, 23 in the form of spring dishes, which can slide on the piston rod 2 I, a movement which is, however, limited by nut 24, 25. Between the discs 22, 23 a compression-spring 26 has been enclosed. The discs 22. 23 further slide along the stationary rods 21, 28, on which their movement is limited by nuts 29, 30 on one side and nuts 3|, 32 on the other side; When the piston 20 moves to the left (starboard), the disc 23 is checked by the nuts 3I, 32 and the spring 26 is pushed in by the disc 22. When the piston 20 moves to the right (port), the disc 23 pushes in the spring 26 and the disc 22 is checked.

The piston rod 2I is pivotably connected at 48 to the hinge 43, which in turn is pivotably con, nected to the pivot 33 of the lever 34, the other end (35) of which is connected to the rod 36. engaging the crosshead I at 31. The iulcrums of the levers I6 and 34 coincide in the point 36. is a stationary. fixed point.

The cylinder I 9 can be isolated from the two hydraulic systems by means of the valves 60, while the hinge 43 can be swung over and connected to the stationary point 5I by disengaging it at 48 and turning it round the point 33 through 180 deg. The known system is then left and the spring device has been put out of operation, so that, even during sailing, the replacement of a broken spring or other repairs or assembly with respect to the spring device can be carried out.

During such sailing without the spring device in the manner taught by known systems, the safety valve 45 is the sole protection against the risk of excessive pressure, so that this provides a reason for maintaining this safety valve 45 in the application of the present invention. even though the invention is normally carried out with the application of the bypass 6|. 7

This bypass 6| directly connects the two bydraulic systems when, owing to the waves striking against the rudder or some other involuntary deflection of the rudder, the piston 20, on the critical pressure being reached, has passed sufflciently beyond the central position opposite the said conduit BI on one side or the other for the in the adjustment of the opening pressure of the safety valve 45 (with slightly higher pressure) and the maximum displacement of the piston 20 (with slightly lower pressure of the springs 26 on the piston 20 reaching the bypass position) the fluid may then be bypassed, at least substantially, through the bypass6l.

It may be observed that the pump, when moved with the aid of the actuating rod 11- the rudder immediately following until it has acquired the desired deflectionis always returned to its central position bythe rod 36 adjusting the fulcrum 38 of the lever I6 in that direction. This is, therefore, a real follow-up movement.

If in applying the. invention the rudder is struck by the waves, for example from port, the torsion thus created in the rudder shaft 3 and the crosshead 1 respectively is propagated to increase the pressure acting on the ram plungers in the cylinders 2 and 3 and to accordingly reduce the pressure of fluid in cylinders I and 4 acting on the two other plungers, the said increase of pressure in the cylinders 2 and 3, acts via the conduit II and port Ila on the starboard surface of the piston 20, tending to-move piston 20 to the right from the position shown in Fig. 1 against the tension of the springs 26 while expelling a corresponding quantity of fluid from the cylinder I9 through port Illa into the cylinders I and 4. If the pressure difference remains below that to which the safety valve is adjusted, the rudder is returned to the desired position by the mere spring tension as soon as the wave is spent.

However, to achieve this the pump I4 should i remain untouched in its central position during the fluctuation, so as to prevent the deflection being obviated, counteracted or made impossible, entirely or partially; this is prevented by the system of rods 2|, 34, 36, connecting the crosshead I to the piston 20.

If, however, due to accidental deflection of the rudder, the hydraulic pressure difference increases to the critical pressure difference, the rudder first acts against the spring tension, and only then the safety valve 45 is opened, the piston 20 stops its yielding movement at that moment and at the same time the displacement of the pivot 33 is stopped. The rudder 9, and simultaneously the point 35, continue their movement due to valve 45 being open so that the lever 34 rotates about the point 33. Thus, the pivot 36 is bound to follow the pivot 35, thereby shifting lever I6 about pivot 33 and actuating lever I3. Consequently, from the moment at which the critical pressure is reached, pump I4 is put on delivery stroke and, this time in combination with the tension of the springs, bring about the return of the rudder to the desired position. In other words, if-with regard to Fig. 1, the piston 20 had moved leftwardly due to accidental clockwise movement of the rudder 9 and thus increased pressure in cylinders 4 and I, fluid will be by-passed, first through passages 6| and then through valve 45 from conduit III to conduit l I. Thus, cam will move upwardly so that the accidental movement of the rudder is not opposed. While rudder 9 moves in clockwise direction, rods 36 and I8 move rightwardly. This puts pump H on delivery stroke and causes pressure fluid to be delivered into cylinders l and 4. After the same has spent its force and valve 45 is closed again, the last mentioned fluid pressure plus the action of the left side springs 26 return the rudder to its previous position.

Thus, with any more or less heavy seas the rudder either acts against the spring tension, without being counteracted by the pump l4, and is returned by the mere spring tension, or first acts against the spring tension, without being counteracted by the pump I 4. before the bypass through valve 45 becomes eflective, and is returned to the desired position by the spring tension and the pump combined.

In explanation it may further be stated that the initial tension of the springs 26 is calculated and adjusted to or slightly in excess of equilibrium with the resistance of the rudder on board, the water being quiet and the ship sailing at full speed.

The said system of rods has no other function but creating a temporarily stationary fulcrum 38 on the lever 34-namely for the period of the said fluctuation-for the lever IE to be connected to its fulcrum, so as to prevent the pump II from coming into operation during the aforementioned fluctuations of the rudder.

During the displacement of the-point 35, together with the rudder 9, and of the point 33,

together with the piston 20 in opposite directions,

the point 38, indicated only diagrammatically, remains stationary.

What I claim is:

1. A hydraulic steering mechanism comprising in combination, steering means arranged for controlling the rudder of a vessel, a first hydraulic system associated with said steering means for moving said steering means in a first direction, a, second hydraulic system operable for moving said steering means in a second direction, pump ing means for supplying actuating fluid to either of said hydraulic systems, and yielding means interposed between said hydraulic systems and arranged in response to accidental increase in pressure in either of said systems temporarily to increase the volume capacity of the system in which the accidental increase occurs.

2. A hydraulic steering mechanism comprising in combination, first fluid operable motor means provided with oppositely effective areas operable respectively and selectively as suction and as pressure sides, second fluid operable motor means provided with oppositely eifective areas operable respectively and selectively as suction and as pressure sides, steering means arranged for connection with a rudder and having two spaced pivot points connected with said first and said second operable motor means, reversible variable delivery pumping means associated with said first and second fluid operable motor means for selectively supplying actuating fluid to and withdrawing fluid from said first and second fluid operable motor means, first conduit means arranged for interconnecting the respective pressure sides of said first and second motor means, second conduit means arranged for connecting the respective suction sides of said first and second motor means, yieldable separating means interposed between said first and second conduit ing means for continuously urging said separating means into a predetermined neutral position for making said by-passing means ineffective, and

lever means operatively interconnecting said steering means, said separating means and said pumping means.

3. A hydraulic steerin mechanism comprising in combination, steering-means arranged for controlling the rudder of a vessel, hydraulic rams operable to effect movement of said steering means, reversible variable delivery pumping means for supplying actuating fluid to said rams, first conduit means connecting said pumping means with a first group of oppositely effective areas associated with said rams, second conduit means connecting said pump with a second group of oppositely effective areas of said rams, separating means interposed between said first group and said second group of areas and yieldable in response to accidental increase in pressure acting on either of said two groups, by-pass means controlled by said separating means for interconnecting said first and said second groups of areas in response to said accidental increase in said pressure, yielding means associated with said separating means for continuously urging said separating means into a predetermined neutral position for making said by-passing means ineffective, and lever means operatively interconnecting said steering means, said separating means and said pumping means.

4. A hydraulic steering mechanism comprising in combination, steering means arranged for connection with the rudder of a vessel, first hydraulic motor means pivotally connected with a first pivot on said steering means, said hydraulic motor means being provided with a first group of oppositely effective fluid pressure responsive areas, second hydraulic motor means pivotally connected with a second pivot on said spring means, said second hydraulic motor means being provided with a second group of oppositely effective fluid pressure responsive areas, first conduit means connecting one of the areas of said first group with a corresponding area of said second group, second conduit means connecting the other area of said first group with a corresponding area of said second group, control means interposed between said first and second conduit means and normally preventing direct.

communication between said first conduit means and said second conduit means, said control means being operable in response to an accidental increase in pressure on one of the areas of either group to increase the volume of the respective motor means temporarily, reversible variable delivery pumping means associated with said first and second motor means for supplying actuating fluid thereto, yielding means associated with said control means for continuously urging the latter into ineliective position, and lever means interconnectingsaid control means, said pumping means, and said steering means.

5. A hydraulic steering mechanism comprising in combination, steering means arranged for connection with the rudder of a vessel, first hydraulic motor means pivotally connected with a first pivot on said steering means, said hydraulic motor means being provided with a first group of oppositely effective fluid pressiire responsive areas, second hydraulic motor means pivotally connected with a second pivot on said steering means, saidsecond hydraulic motor means being provided with a second group of oppositely efl'ective fluid pressure responsive areas, first conduit means connecting one of the areas of said first group with a corresponding area of said second group, second conduit means connecting the other area of said first group with a corresponding area of said second group, control means interposed between said first and second conduit means and normally preventing direct communication between said first conduit means and said second conduit means, said control means being operable in response to an accidental increase in pressure on one of the areas of either of said groups to effect communication between said first conduit means and said second conduit means, yielding means associated with said con trol means and continuously urging said control means into neutral position for preventing communication between said first and said second conduit means, a first lever means connecting said control means with said steering means, reversible variable delivery pumping means for supplying actuating fluid to said first and second motor means, and second lever means pivotally connected to said first lever means and operatively connected to said pumping'means for controlling the delivery and direction of delivery thereof.

6. A hydraulic steering mechanism comprising in combination, steering means arranged for connection with the rudder of a vessel, first hydraulic motor means pivotally connected with a first pivot on said steering means, said hydraulic motor means being provided with a first group of oppo-- sitely efiective fluid pressure responsive areas, second hydraulic motor means pivotally connected with a second pivot on said steeringmeans, said second hydraulic .motor means being provided with a second group of oppositely eiiective fluid pressure responsive areas, first conduit means connecting one of the areas 01 said first group with a corresponding area of said second group, said conduit means connecting the other area of said first group with a corresponding area of said second group, a cylinder piston anangement interposed between said first and said second conduit means and operable in response to an accidental increase in pressin'e on one area of either of said groups to increase the capacity of the conduit means leading from the respective area under accidental increase in pressure to said cylinder piston arrangement, yielding means associated with said cylinder piston arrangement for continuously urging the same into a predetermined neutral position, variable delivery reversfirst conduit means connecting one pressure efi'ective area of one motor means with an oppositely eflective area 01' the other motor means,

second conduit means interconnecting the other two eiiective areas of said two motor means, reversible variable delivery pumping means for supplying actuating fluid to said motor means, first lever means associated with said pumping means for controlling the delivery and direction of delivery of said pumping means, controlling means interposed between said first and said second conduit means and operable in response to an accidental increase in pressure on either of said eiiective areas for temporarily increasing the capacity of the conduit means associated with .the respective area under accidental increased pressure, yielding means associated with said control means and continuosuly urging said control means into its ineflective position, and second lever means operatively interconnecting said control means with said steering means and pivotally supporting said first lever means.

8. A hydraulic steering mechanism comprising in combination, steering means for connection with the rudder of a vessel, a pair of hydraulic motor means respectively provided with oppositely effective pressure responsive areas and livery of said pumping means, controlling means interposed between said first and said second conduit means and operable in response to an accidental increase in pressure on either of said effective areas for temporarily increasing the capacity of the conduit means associated with the respective area under accidental increased pressure to thereby relieve said accidentally increased pressure, yielding means associated with said con trol means and continuously urging said control means into its ineiiective position, andsecond, lever means operatively interconnecting said control means with said steering means, said first lever means and said second lever means including a lever having the same fulcrum supported by one of said two levers.

ible pumping means for supplying actuating fluid to said first and second motor means, first lever means associated with said D mping means for controlling the delivery and the direction or delivery of said pumping means, and second lever means pivotally supporting said first lever means and operatively interconnecting said steering means with said cylinder piston arrangement.

7. A hydraulic steering mechanism comprising in combination, steering means ior connection with the rudder of a vessel, a pair of hydraulic motor means respectively provided with oppositely efiective pressure responsive areas and pivotally connected to spaced points of said steer- 9. A hydraulic steering mechanism comprising in combination, steering means for connection with the rudder of a vessel, said steering means being provided with two spaced pivots, first hydraulic motor means provided with a first group of oppositely eflective pressure responsive areas and pivotally connected with one of said pivots, second hydraulic motor means provided with a second group of operatively effective responsive areas and operatively connected with the other pivot of said steering means, first conduit means arranged for eifective communication between an eflective area of the first group with an operatively eii'ective area of the second group, second conduit means for interconnecting the other two efiective areas of said first and second motor means, control means interposed between said first and second conduit means and operable in response to an accidental increase in the pressure on any of said effective areas for temporarily ining means for actuation of said steering means, 15 creasing the fluid capacity associated with said last-mentioned area to thereby relieve the accidental increased pressure thereon, yielding means associated with said control means for continuously urging said control means into ineifective position, means operatively interconnecting said yielding means and said control means, abutment means for limiting the movement of said control means within predetermined limits, pumping means of the variable reversible delivery type for supplying actuating fluid to said motor 1 means, first lever means including a plurality oi levers for controlling said pumping means, and second lever means including a plurality of levers operatively connecting said steering means with said control means, one of said levers of said second lever means pivotally supporting a lever means, second conduit means interconnecting the other two effective areas of said two motor means, reversible variable delivery pumping means for supplying actuating fluid to said motor means. first lever means associated with said pumping means for controlling the delivery and direction of delivery or said pumping means, controlling means interposed between said first and said second conduit means and operable in response to an accidental increase in pressure on either of said eil'ective areas for temporarily increasing the capacity of the conduit means associated with the respective area under accidental increased pressure, yielding means associated with said control means and continuously urging said control means into its ineffective position, second lever means operatively interconnecting said control means with said steering means and pivotally supporting said first lever means, and emergency means also interposed between said first and second conduit means and independent of said control means to allow flow of fiuid from one conduit means into the other conduit means in response to a predetermined accidental high pressure in either of said motor'means.

PETER. JACOBUS NOORDEMAN.

REFERENCES CITED The following references are of record in the file 01' this patent:

UNITED STATES PA'I'ENTS Number Name 7 Date 1,056,194 Martineau Mar. 18, 1913 1,638,786 smith Aug. 9, 1927- 2,125,452 Lamond Aug. 2, 1938 2,139,604 Riddell Dec. 6, 1938 2,387,307 Stone Oct. 23, 1945 

